Will quantum computers break the blockchain?

Coinbase CEO Brian Armstrong has characterized the quantum computing threat as a "solvable problem" and is working to take preemptive action by discussing upgrade paths with major blockchains and establishing an independent advisory board. The board includes leading researchers in quantum computing and cryptography, including Scott Aaronson, Dan Bonneh, and Justin Drake, and aims to provide guidance to the entire ecosystem beyond simply protecting its own company.

On the other hand, a16z crypto and others have sounded the alarm that the timeline for quantum threats is often overstated. They predict that the emergence of a quantum computer large enough to break encryption is unlikely within the 2020s, and argue that response priorities should be carefully determined based on the nature of the information (encryption for confidentiality, signatures for authenticity).

Behind these discussions lies the technological reality surrounding the current state of quantum computing. Quantum computers are by no means omnipotent, omnisearch machines, and currently appear to face a major obstacle: errors.

According to NIST (National Institute of Standards and Technology), current quantum bits are extremely vulnerable to external disturbances, with errors occurring at a frequency of about one in every thousand operations. This vulnerability is the biggest obstacle to scaling up computers.

In recent years, Microsoft and Quantinuum have demonstrated dramatic improvements in reliability using logical quantum bits in quantum error correction (QEC), a technology designed to overcome these errors. However, this still remains far from the scale of millions of bits required for decryption. The engineering hurdles for running Shor's algorithm—a number-theoretic algorithm running on a quantum computer with destructive computational power that threatens the very foundations of modern digital security—at practical speeds remain extremely high.

In conclusion, the debate over the quantum transition should not be reduced to a simplistic binary choice: "will quantum come to an end?" Rather, in the face of this uncertain future, it could be said that a long-term race to adapt has begun to see which industry has the ``coordination ability'' and ``execution ability'' to carry out the massive replacement of encryption infrastructure.